I would imagine now with trackage rights to salem there is less freight movement on the westside line between Sherwood and McMinville? If I remember right there is a pretty stiff grade somewhere along that segment.
There is a grade over Rex Hill but it's not insurmountable. The bigger problem is maintaining all the wood trestles on that route, and the fact that most of the traffic coming out of McMinnville and the Willamina District goes to California, so why not just send it to Albany and not deal with the grades or the bridges. Wouldn't surprise me if it gets abandoned for a bike trail; it's been studied to death for commuter rail and shockingly, each report gives commuter rail a dim view on the route - the last study said it might pencil out to Newberg but not to McMinnville.
SP Newsprint in Newberg is all but shut down so trains only run north of McMinnville as-needed; I believe the only real freight is hog fuel (old railroad ties) going to feed the power plant; no scrap paper in or newsprint out.
Cascade Steel lost a lot of traffic to trucks - a lot of the scrap that used to go to CSRM from Portland now is trucked in.
Willamina Branch is down to one sawmill (Willamina Lumber - Hampton) shipping; Fort Hill is gone, Conifer is gone, Boise hasn't shipped in decades, and I don't think the pole companies are shipping by rail nor is the small mill in Sheridan. Not the time of year for agricultural traffic in/out of Sheridan or Ballston.
Dallas Branch is embargoed and stuffed with well cars. Boise in Independence is shut down just as Weyerhauser in Dallas.
The OE simply has a more diverse traffic mix and also hits all the big cities that the Westside doesn't.
McMinnville lost Nursery Supplies West (used to receive plastic pellets by hopper for making nursery pots), and the team track downtown is now out of service. All of the downtown ag shippers are long gone; all that's left is Purina Land o' Lakes (the old Mac Feed) at the south end of town. I'm not sure what Buchanan Cellars gets at Whiteson as I believe they did add a spur.